Starter mechanism



June 10, 1930. E. R. WHARTON 1,762,434

STARTER MECHANISM Filed July 1, 1929 Patented lune Mi, ldiitl PATENT FFICE EDWARD R. WHARTON, OF MEDFORD, MA$SACHUSETTS STARTER MECHANISM Application filed July 1, 1929. Serial No. 375,218.

{My invention relates to starting mechanisms such as are provided for starting the operation of internal combustion engines, and it has for its object to provide an improved mechanism of this class.

One type of starter mechanism of the class referred to is constructed with two members mounted upon the armature shaft of the starting motor which are both movable relative to said armature shaft rotatively and axially or longitudinally. One of these members has been made with a conical clutch member fitting into a conical socket provided at one end of the other member, the opposite end of the latter being provided with one or more cam surfaces engaged by one or more studs projecting from the armature shaft. The member that is provided with the male conical clutch portion had compounded with it a spur pinion that was normally held out of mesh with the driven gear of the engine by means of a spring. When the motor of a starter mechanism of this type is started, the stud on the armature shaft thereof operates through the cam surfaces referred to to move the twomembers axially on the shaft toward the driven gear against the pressure of thespring. This axial movement not only carried the pinion into mesh with the driven gear, but operated, or was intended to opcrate, so as to causethe male conical member to frictionally engage the female socket member so that the pinion was not only meshed with the driven gear but also rotated from the armature shaft to start the engine. As a matter of fact the conical member has heretofore necessarily been made of such a 'taper,in order to obtain the necessaryclutching action, as to sometimes freeze or stick rigidly to the female socket mcm er so that the two members would function as a unit, which was objectionable. Another objection to the construction heretofore provided was that lubrication would work on to the conical male member or into the conical female socket member, with the result that the two members would not be clutched together as required in the operation of the device.

My invention is primarily designed to obviate these objectionable features, and it consists of a starter mechanism having the peculiar features of construction and mode of operation set forth in the following description, the several novel. features of the invention being particularly pointed out and defined in the claims at the close thereof.

In the accompanying, d 'awin gs Figure 1 is an elevation of a portion of a startcrmechanism constructed in accordance with my invention.

Figure 2 shows a portion of the armature shaft of the electric motor with the parts mounted thereon in section.

Figure 3 is an end elevation of the female member of the clutch.

Figure 4 is a side elevation of the male member of the clutch with which the driving pinion is compounded.

Figure 5 is an end elevation of the member shown in Figure 4e.

Having reference to the drawings, 1 shows a portion of the usual gear provided on the fly-wheel of the internal combustion engine in connection with which my improved starter mechanism is employed.

Suitably supported adjacent the driven gear 1 is an electric motor 2 whose armature shaft 3 has loosely mounted on it two clutch members 4; and 5. The clutch member 4 is the male member of the clutch and is made conical to fit a complementary conical socket provided at one end of the female member At its outer en d the female member 5, which is in the form of a sleeve, is constructed with two diametrically opposite spiral slots 6, 6, each of which is occupied by a stud 7 projecting from the armature shaft, or rather from a collar 8 that is fixed rigidly to said shaft by means of a set screw 9 that is locked, as usual, against accidental loosening by means of a wire ring 10 occupying an. annular groove provided upon the outside of the collar 8. Each spiral slot 6 provides two opposed cam surfaces 11 and 12.

When the electric motor 2 is started, its armature shaft is driven in the direction indicated by the arrow and each stud acts against the cam surface 11 of its slot to move the female member 5 axially on the armature shaft 3 toward the driven gear 1 against the pressure of two springs 13 and 14.

The male clutch member 4 has compounded therewith a driving pinion 15 which is normally just out of mesh with the driven gear 1 as shown in Figure 1. It will therefore be clear that when the electric motor is started and the female member 5 of the clutch is shifted toward the driven gear 1, said female member carries the male member 4 with it and the pinion 15 is moved into mesh with the driven gear 1.

The spring 13 is made relatively heavy and of such proportion and length that when the pinion 15 is fully in mesh with the driven gear 1 all of the convolutions of spring 13 are closed together and said spring acts then as a rigid abutment to prevent further movement of the clutch members toward the driven gear 1. The other spring 14 is made considerably lighter and merely serves to hold the two members of the clutch snugly together under normal conditions while the electric motor 2 is at rest and the pinion 15 is out of mesh with the driven gear 1. A cup washer 16 is interposed between the adjacent ends of the two springs as usual.

In proceeding in accordance with my invention the male clutch member 4 is made conical as heretofore, but of much blunter taper than it has heretofore been possible to use, for the reason that I provide the conical exterior of this member 4 with longitudinally disposed ribs 17 each occupying shallow longitudinal grooves 18 provided within the conical portion 19 of the female member 5. These ribs 17 and grooves 18 are made rounded and comparatively shallow.

It will thus be seen that in my new mechanism the two clutch members are not only frictionally coupled together through the engagement of the conical male member with the conical socket of the female member, but said members are provided with complementary grooves and ribs which intermesh so that rotative-motion is transmitted from the female member to the male member through the engagement of opposed shoulders on said member, as well as through the frictional adherence resulting from the conical shapes of the co-acting parts of the two members. Thus, I am enabled to make the male member of such a taper that it will not freeze within the female member and at the same time the inter-engaging ribs and grooves ensures operation of the clutch even though the contacting surfaces of the two members may accumulate lubrication. It will be understood that the purpose in making the ribs 17 rounded in cross section is to permit said ribs to ride out of the grooves when the rotation of the pinion 15 is opposed to an injurious extent by the gear 1.

The studs 7 act against the sides 11 of the slots 6 to shift the two members of the clutch toward the driven gear 1 and also to rotate said members as usual when the electric motor 2 is first started, and as soon as the internal combustion engine starts up, the sides 12 of the slots 6 act against the studs 7 and in co-operation with the spring 13 to restore the two members 4 and 5 to their normal positions. at the limit of their movements away from the driven gear 1.

What I claim is:

1. In a starter mechanism of the class described, the combination with a driven gear, of a driving shaft provided with a radially projecting stud; a clutch member consisting of a sleeve loosely mounted on said shaft made at one end with opposed camsurfaces co-operating with said stud and adjacent its opposite end with eccentrically positioned recesses; a second clutch member loosely mounted on said shaft made at one end with eccentrically positioned beveled lugs to mesh with the recesses of said first member and at its opposite end with a pinion to co-operate with said gear, and spring means on said shaft engaging said second clutch member to yieldingly hold both members at the limit of their movement away from said gear.

2. In a starter mechanism of the class described, the combination with a driven gear, of a driving shaft provided with a radially projecting stud; a clutch member consisting of a sleeve loosely mounted on said shaft made at one end with opposed cam surfaces co-operating with said stud and at its opposite end with a conical socket formed with longitudinal grooves; a second clutch member loosely mounted on said shaft made at one end with a conical portion to fit within said socket formed with longitudinally disposed beveled ribs to mesh with the grooves of said socket and having at its opposite end a pinion to co-operate with said gear, and spring means on said shaft engaging said second clutch member to yieldingly hold both members at the limit of their movement away from said gear, with the ribs of said conical portion occupying the grooves of said socket.

3. In a starter mechanism of the class described, the combination with a driven gear, of a driving shaft provided with a pair of radially projecting studs; a clutch member consisting of a sleeve loosely mounted on said shaft made at one end with spiral slot-s occupied by said studs and at its opposite endwith a conical socket formed with shallow longitudinal grooves having beveled side Walls; a second clutch member loosely mounted on said shaft having at one end thereof a conical portion to fit Within said socket made With longitudinally disposed ribs to mesh with the grooves of said first member and provided at its opposite end with a pinion to cooperate with said gear, and spring means on said shaft engaging said second clutch member to yieldinglv hold both members at the limit of their movement away from said ear.

a Signed by me at Boston, Sufiolk County, Massachusetts, this 25th day of June, 1929.

EDWARD R. WHARTON. 

